Electrical connector



P. NEILL ELECTRICAL CONNECTOR Sept. 14, 1943.

Filed oct. 51, 1940 s sheets-sheet 1 /NVEA/TOR K R NE/LL MMT HUH

ATTORNEY Sept. 14, 1943. P. NEILL ELECTRICAL CONNECTOR Filed Oct. 51, 1940 3. Sheets-Sheet 2 Sept. 14, 1943. P. NEILL ELECTRICAL CONNECTOR y -Filed Oct. 51, 1940 3 Sheets-Sheelt 3 9 w. zw .T n A @vh ..0 (.lvl G muh :11| l Ill F 3 v y uw n m 5 1--: T l- -l m M-- 1 Il F w 3 l 3 J J. w a am.

ATTORNEY' Patented Sept. 14,' 1943 ELECTRICAL CONNECTOR Paul NeilLEast Orange, N.'v JL, assigner' to Bell'lj Telephone Laboratories,

Incorporated', New

York,N; Y., a corporation of New York A Application October31, 1940, Serial No. 363,"2'27- 12 claims. (C1. 17a-aon This` invention relates to'- electrical connectors of the plug-in type and particularly to multifinger plugs Hofy thevtype--commonly employed in the telephone plant. f

In telephone practice, telephone toll` station are interconnected bylineans of toll lines-which usually pass through several intermediate offices located at intervals betweenvthe toll stations and are accessible at theseseveral ofiicesfor testing 1 purposes. At such intermediate oiiices, the toll lines and associated equipment are interconnected by jacks,- by means of which a test opera-tor or. attendant may gain access to thelines, or equipment, by plugginginto lthefjacks for the purpose of 'interchanging or connecting he necessary test apparatus to the line. A-twin jackl designed for. this purposeis disclosed in U. S. Patent 2,032,191, issued February 25, 1936, to G. P. Tromp-etal. As such toll lines are usually composite innature, that-l is, designed to carry both telegraph and speech currents, it is essential that nointerruptions of the line yoccur when the equipment. is changed or the test apparatus is connectedto the line, lest the printing telegraph equipmentassociated with the line respond tol such interruptions and cause serious mutilation of thettelegraph messages being transmitted.r Such breaks, in the Ytelephone and telegraph arts are known as hits f It is the-object of thisinvention tov provide an improved multifingerplug which minimizes the possibility of circuit interruptions, or"hits when used to associate test apparatus orsimilarzinstrumentalities ,with a. transmission line.`

This object is attained, in accordance with aL l feature of vthe, invention;v bythe provision of a multinger plug whichfunctions to insure circuit continuity through kthe instrumentality which terminates in the plug, before the plug opens the line with which the instrumentality is Lto be associated. More speciiically, the plugk of this invention is provided with pairs of tip connector elements which are freetomove longitudinally with respect toy their respective plug sleeves, and'with means for preventing any one tip. connector from operating its corresponding jack spring untilthe other tip connector of a pair has engaged its corresponding jack spring. Thus, any instrumentality, suchas a test circuity a patching cord, a spare repeater or the like, is electrically included in the transmission line without the line being opened or otherwise Adisturbed due to the temporary change in conditions. This structural feature of the plug serves'to compensate for, any mechanical variations inthe. jack which might;

otherwisecause thefalinefcontacts toopen sequentially, ratherA than, simultaneously when a `multiiin'gerplug'is insertedzinl the' jack.. t

Another: feature of. theinvention resides in the use ofmeans formechanicallylocking the-plugin the. jack with which; the, plug 1unctions-.

A furtherA feature of the invention `conteur-- plates the usef of means.'` which. functions l to.- per` mit the tip'connectorstobe. moved; into andv out of; yengagement with their correspondingY jack contactsv while thenplugfis` effectively, locked in.y

position,thus further: insuringfagainst the possi-A bility of hits, particularlywhen the-plug isvbefv ing removed from the-iack.-

These andi other' featuresof thevinvention will be; readily understood yfrom .the iollowing detailed descriptionA madev with reference,tov theA accompanying:drawings-inwhich: n t. y

Fig.' `1 is atopzelevation or plan View ci the plug structure of this invention with a prtionof theplugshell brokenaway to reveal the interior construction. Infthis ilgurezthefupper plug finger illustrated; is one of a pair-,of plug ngers, `whereas theylower plugiinger is onecf another pair, itl being'understood thatY a fingen` similar vto, veach ofv the; plug1fingersshown, isilocated inthe back of. those illustrated; A

, Fig. 2is apartiall sectional view` taken along the lineZ--Z of Fig..1` andqlooking-,in the directionv of :the arrows.` In thisview, the upper plug nger' corresponds to 4theupper finger of Fig.. 1, andthe lower finger is they plug finger` paired with-,the 'upper finger. ln'otherxwords,A the two plugingers shownin Fig. 2-constitute apair;y Fig. ,3 is a sideview of the plug with a'portionV ofy the ,plug shellsr andf of Y other` details broken away;V to show the'- interior lconstruction kofthe plugfaswellf'as lthe general plugii-nger construction., In this view-'theilockingmechanismlis 1inoperated;vv l y f f v Fig; V4i is af-,view generally similar to rthatnof Fig, ,and in'which thelocking mechanism is in itszoperatedppsition.and thegtip connectors vare shown relativelydisplaced; y y...

F1g.5 Yis a. front viewrtakenalc-ngrthe line. 524-5 of Fig; 3, looking; in the.directicnrofthe arrows; Figg'is a front viewtaken alongthe-.li'neBT-S ofFig. 4, looking'r in the'direction of the arrows; Fig. '7 is, a-section-,taken along the line, T-l of Fig. 3,- looking^ in the dir'ectionvofthearrows; and f i Fig.Y 8 is. a circuit-.diagram illustrating the, line wires of' a :transmission ',linepassing'f throughA the contacts of a palrof twin jacksof thetype with which the plug of this ,inventionffunctions In this figure, the jack contacts of the left-hand pair of jacks a, b would be engaged by the tip connectors of one pair of plug fingers, whereas the contacts of the right-hand pair of jacks c, d would be operated by the tip connectors of another pair of plug fingers.

In the drawings, wherever possible, the elements comprising the plug fingers of one pair of fingers are identified by unprimed numerals, whereas the corresponding elements of the other pair of plug fingers are identified by the same numerals primed. For example, the elements of the pair of plug fingers shown in Figs. 2 and 3 bear the identifying numerals I0, I2, I3, I4 and I6, whereas the corresponding elements of the other pair of plug fingers, only one of which appears in Fig. 1, bear the identifying characters I2', I3', I4 and I6. It is to be understood that the plug pictured in the several figures, in reality, comprises two twin plugs combined in a unitary structure, rand each pair of tip. connectors I4, I4 and I4', 'I4'. have their own individual operating rocker arm 50 and 5|, respectively, as will be more fullydescribed hereinafter.

The plug structure is housed in a tubular rectangular metal shell 5, one end of which is provided with a cap or cover 6 of ksimilar material and the other end` ofvwhich is open. Each of the four sides of the shell 5, near its open end, is

provided with a small centrally located aperi,

ture, each of which accommodates a screw 1, by virtue of which the shell is held in position on the finger mounting member 2|.

The finger mounting member 2| is an integral unit, and as Viewed in Figs. 5 and 6 consists of three horizontal legs I, 2 and 3 jointed by a centrally located vertical leg so as to provide four slots, two of` which are indicated by the numeral 22 in Fig. 2. Each of these slots provides a housing or bearing for a plug finger.

Since each of the plugl fingers are identical in construction, except in one detail, which will be referred to presently, the structure thereof will be described with particular reference to Fig. 3. Each plug finger comprises a tubular sleeve whose intermediate section I2' is larger in diameter than either of its two end sections I0 and 4. The section of each of the upper fingers (as` seen in Figs. 5 and 6) have two flat sides intercon-` nected by a semicircular portion, whereas this section of thev lower flngers,'Figs. 5 and 6, has but one at side. The end portions I0 and 4 are circular in section. Each of the end portions 4 of the-several fingers terminates in a circular flange II. An insulating bushing|3 is tightly fitted into the outer ends of each of the sleeve portions I0 and 4. 'I'hese bushings serve as bearings for the tip connectors I4', which are arranged to freely move longitudinally therein. Each tip connector I4 or I4 is provided with a contact I6 or I6 at itsouter end, and with aterminal bearing element I5 at its inner end. The outer end of each tip connector is knurled longitudinally or otherwise fitted to accommodate its respective contact I6 or I6', whereas the rear end of eachv connector is threaded to receive its respective termin-a1 piece I5. Interposed between the flanges II of ,each plug sleeve and the. rear face of the mounting member or plate 2| .is an H-shaped spring 26, which serves to permita limited amount of play between the plug'sleeves and their mounting apertures 22. On either side of the mounting plate 2 I `there is provided a metal their respective plug sleeves have been inserted therein. The screws 1, one on each side of the forward end of the shell 5, serve to secure the mounting 2| and its side plates 23 in position within the forward end of the shell.

The rear face of the mounting plate 2| is provided with a slot or groove, indicated at 4| ln Fig. 2, which accommodates a substantially rectangular plate 4|). The slot 4| is centrally located, and, viewing Fig. 2,`extends vertically, whereas in Fig. l the position of the slot is horizontal. The plate 40 is permanently fitted in the slot 4 I.

The plate 40 is provided with a centrally located slot 42 which extends half-Way from one end toward the end which is fixed in slot 4|, and with -a smaller slot 43.f Two oppositely disposed brackets 46 and 41 are mounted on an element arranged to slidably move in the slot 42. This element consists of two integral portions, a substantially rectangular portion 44 `and a smaller rectangular portion 45, the latter being just wide7 (viewing Fig. l) carries an insulating rocker arm such as 50 or 5| which arms are pivotally mounted at their centers on the screws 10 or 1|, respectively. The upper bracket 46 is provided with a screw Whose head extends into the slot 43 in element 40 and serves to limit the extent to which the slidable element A44--45 may bemoved. This screw serves tofprevent breakage of the connectingwires 16 by preventing the slidableelement 44-45 from being withdrawn when the cap 6 and knob 62 are removed.

The outer extremity of Aportion 44 is provided with a T-shapedslot 64 into which the correspondinglyshaped end of a turn screw 6| is adapted to be fitted and to be capableof substanl tially universal movement therein. `The turn screw Y6| is provided at its outer end with a finger grip or handle 62.

The vertical portions of the brackets 46 land 41 (viewing Fig. 1) serve to support a. lcommon insulating terminal strip |10 which carries four terminals, such as I1I and |12, to which the leads 13 and 14 may be connected in any suitable manner. lug 15 to which maybe soldered one end of the lead wires 16, the other endsthereof being soldered to terminals 11 carried by the terminal bearing elements I5.

On either side of the plate 40, there is mounted an insulating block 19, each of vwhich is so positioned with respect'toa different pair of terminal bearing elements I5 as to Yprevent the latter and their associated tip connectors I4, I4 from rotating throughany appreciable arc.

The turn screw 6I `is adapted to be rotated in anism, which consists, essentially, of a pair of,

bowed springs 29, a pair of clamping jaws 3|)r and an operating handle 3|.

Each of these .terminals ls provided witha The bowed springs acca-glo 2,9 'are interposed betweenrthe clamnngmember 3u and have their apices contacting, .so that the bows of the-twosprings vare reversed relative ,to one another. ,A The clamps 3.0.and `springs' 29 are each .provided with a .centrally `located hole through which a pin .32 extends rin passing through aligned holes .in the lugs 21. and 2B. The operating handle is secured in any'v suitable manner to one end of the pin`32. :Aspacing washer 33 isv interposed .between the handlel y3l and the upper face'of lug `28. Immediately below the lug 28 there is pinned or otherwise xed ,to the pin shaft 32 .asleeve 34, whose lower end is yout from thecenter line at `diverging .angles toeifect acam. This cam endof sleeveiunormally restsin a. triangular trough v35 effected byA integral projecf tions on the upper `face of the upper clamp 30.

In Fig. the clamp members 30 are shownseparated to a maximum extent. :In this position the bowed springs exert substantially lno pres'- sure on the clamps other than that required to hold them inthe position shown. -When the vharidie 3| is movedIthrough an arcof substantially 90 degrees, la similar movement-is impartedto the pin shaft 32 and `its associated cam' sleeve 34. During this movement, the cam end of sleeve 34 acts upon the inclined faces of the -trough 35 causing the upper clamp'to movedownwardly and compress the springs 29 as shown in Figs. 2 and 6. When the sleeve 34 Vis rotated through anarc slightly greater than y90'degrees, the high points of its cam end rest upon the 'top of thel sides of trough 35 so that `the clamps 3E! are locked in the position shown in Fig. 6.v The lower clamp 30,

accordingly, exerts a downward vpressure on Vthe .2:

In `this position of the p1ug in the jack, and

with the slidable element dll-'.45 withdrawnr to its outer extremity, the tip contactsl and'l may or may not contact their respectivejack tip springs and preferably would vnot, though no jack-spring operating function is performed vuntil after the plug iS lockedin position. IThe handle 62 is then turnedto advancey the screw 6 I ,inward-K ly'through the coverr4 6. This movement forces the slidable elementM-ll to moveinwardly, carrying with itthel rocker arms and 5|. As the rocker arms 53 and 5I advance with tl'ieirsup-4 port M -'45, they engage the rear edges of the ter- L outwardly from the plugthey engage c'orresponding jacksprings such as 9 0 and SI (Fig. ,3)1 and cause them to bey moved out of engagementwith their associated springs. and to thus open the line circuit. Should the jack springs 90 and 3|, for example, vary in position with respect to the kjack center `line or in .distance from .the jacky face eitherr y one or vthe other contacts I6 (Fig.3)y would engage its yjack spring before theiother lengaged its corresponding jack spring. In such acaso, the ltip connector I4. whose contact I6? first engaged its jack spring (SI, for example) Iwould ibe held against further longitudinal ,movementbyfthe jack spring pressure, and continued rotation1 oi the handle 62 v would `result in y.a rotational imovement of tiieiocklerv :arm fil about its pvot Surfport -H tocause the oi'fhertip'conneciforlIl.4 ,t0 be advanced luntil its contact '11.6"' came inrcontaot' with `its corresponding jack'springrll. This con.-l dition is illustrated in Fig. 4- `Whenlioth con-y 'tacts lare in engagement `with their respective or other instrumentality connecteditothe leads I3 01x14 has.I been `effectively ,included in vthe line. The possibility .of a;hit is thus; eliminated. It willgbe understood that, Ithough .the immediately preceding description 'has beendirected vto .the

operationof rocker arm ;5:|' and .its associated tip connectors I4", the Esameapplies .equallyy well to the .operationof rocker arm 53 and .its .associated i tip connectors I4. i y i y To provide a .morecomp'lete understandingiof the plug .structure andf itsroperation, particular reference will. now vbe made tohF-igz in conjunction with they other figures "of the drawings. In Fig..8 there is shown la toll vline rL, L :which passesfthrough iin-intermediate oiicenat which thejacks'a, '11, c and'd are located.' vNormally; the conductors of the line"L;-L' arerendeifed continuous :by means of thefsprings 'of -jacks a, yb, c ,and d in their` normal condition. lIi it is de sirable for an j .attendant at the intermediate Qice .to gain accessto the .line L, L', this would be .accomplished lby utilizing a plug such asi-is shownin Figs. 1 to 7, inclusive.`V The plug would beso associated with` the jacks that the plug ngerswhose' tip connectors terminate incon-v tacts I6. kwould :be inserted injja'cks a and-b While ,the plug :fingers :whose tip connectors vterr'- minateiincontactsflli would Lbe inserted in' jacks cfand'd; Anexamination of Fig. 8 rendersit obvious that unless thetest equipment associated with lead14,'for example, is connected to vboth jack `springsI and9.l beforeeither; oil -fthese springs is moved'. out of .engagement with its mating spring, '.thejline yconductor which passes through .jacks aand b would experience anopen;

Qr'fhitf?. 1 i i The possibility of either -springSO or YSI being moved pout of engagement with its matingspring before .bothy tipconnector contacts-I6 come yinto contactxwith. their `corresponding jack y'springs 90 forg`9l. Gand, therefore, before Athe line conductor vis rendered continuous through the lead 1.4 land itsassociate'd test equipment, is eliminated by the'plug structure of this invention.,l

as.describedhereinbeforey y i When the plug is inserted in the jacks in the manner described above, the locking lever 3I is' `actuated to cause the upper clamp 30to compress bow springs 29and .thus force the lower clamp `3|),tightly,` against the portions I2 and I2 of the two lower plug iingers. In this manner the plug` is effectivelyvlocked inthe jacks., The

knob v6 2`, is then rotated in vsucha manner as n tocause the vscrew 6I toeadvancery through the cover 6 into the, interior Iof the shell 5. The longitudinalmovement of :scrrewvl isimparted to the sliding'member All-45 which causes the rocker arms and 5I 'to function in the manner. fullydescribed hereinbefore Since it is equally important that no circuit interruptions or hits occur when the plug is withdrawn from the jacks, the knob 62 is rotated .in a reverse direction to Withdraw the rocker arms and thus free thev tip` connectorsi which', due to the action of the jack springs on the contacts I6 and I6', are forced longitudinally in a f backward direction. The mating springs of the jack then contactgthe tip springs, such as 90 and 9|, before the connector contacts I6, I6 1 are disengaged fromthe tip springs. In this manner the continuity of each line conductor is eflected through the jack springs before the test Vapparatus has been disconnected from the conductors.

What is claimed is: 1. In a plug, a pair of plug fingers each hav ing a stationary sleeve, atip connector slidably housed in the sleeve of each of said plug fingers and each connector movable in its respective sleeve independently of the other connector, and manually operable means independent of said tip connectors for sliding said tip connectors in their `ing a cylindrical sleeve, a tip connector arranged to slide longitudinally in the sleeve of each of said plug ngers, a longitudinaly movable sup-` port, an insulating member pivotally mounted on said ksupport and arranged to `engage a tip connector on either `side of its pivot support when said support is moved longitudinally, whereby said tip connectors aremoved longitudinally in the sleeves of their respective .plug

' ngers, and manually operable means formoving said support longitudinally.

4. In a. plug a plurality of plug vfingers having substantially stationary sleeves, an independently movable tip connectorvslidably housed in the .Sleeve of each of said plug fingers, and manually operable means, independent of said tip connectors for slidably moving said tip connectors in their respective sleeves. k l f 5. In a plug, a housing therefor, a pair of plug fingers extending from one end :of said housing and having stationary sleeves, a tip connector slidably housed in the sleeve` of each of said plug lingers and having a contact end protruding from the extended end thereof and a terminal end extending within said housing,qa support within said housing arranged to be movedA longitudinally in a direction parallel to the longitudinal axes of said tip connectors, a rocker arm pivoted at its center on said support andhaving a portion on Veither side of its pivot support in` substantial alignment with the terminal end of a tip connector, and means for moving said support in a direction'parallel to the axes" of fsaid tip connectors whereby the terminal end of eachA of said tip connectors is engaged by the portion of th rocker arm aligned therewith, and the contact ends of said tip connectors are caused to pro-` a plug for association `with saidjack comprising a, pair of plug fingers, each of said plug fingers having a longitudinally movable tip connector, and means effective after said plug has been associated with said jack for simultaneously advancing the tip connectors of said plug fingers to cause them tosimultaneously actuate the contact springs o! said jack."

7. In combination, a multiple jack having a pair of separately operable contactsprings, and a plug for association with said jack having a .pair of hollow plug fingers, each of said plug ngers having a tip connector movable longitudinally, within said plug ngers, and means enective after said plug has been associated with said jack for causing said tip connectors to simultaneously approach corresponding contact springs of said i jack, said means adapted to advance either of said tip connectors individually after the other of said tip connectors has engaged its corresponding jack spring.

8. In combinations, multiple Jack having a pair of separately operable contact springs, and a plug for association-with said jack having a pair of plug lingers, each of said plug fingers having a tip connector movable longitudinally independently of said plug fingers, and means for propelling said tip connectors longitudinally to cause them to approach and engage corresponding Contact springs of said jacks, said means functioning to insure the simultaneous operation of said jack springs by said tip connectors though engagement between said tip connectors and their corresponding jack springs cccurs sequentially, Y k v 9. In combination, contact springs, a` pair of plug fingers, a tip connector slidably housed in each of said plug lingers andhaving a contact at one end thereof for engagement with one oi said contact springs, means for vadvancing said tip connectors into engagement with their respective contact springs, and means for delaying the actuation of either of said contact springs by its respective tip connector until both of said tip connectors have been advanced into engagement with their respective contact springs.

10. In combination, contact springs, a pair of plug lingers having stationary sleeves, a tip connector slidably housed in the sleeve of` each/of said plug fingers and having a contact at one end thereof for engagement with and for actuating one of said contact springs, and means for insuring contact between bothV of said tip connector contacts with their respective contact springs before either of said tip connectors functions to actuat-e its respective contact spring, said means ycomprising a pivoted member cooperating with one end of each of said tip connectors to simultaneously advance said tip connectors in Vtheir respective sleeves, when moved in a direction parallel to the longitudinaly axes of said tip connectors until either thereof engages its respective contact spring; and thereafter to advance the other of said tip connectors into engagement with its respective contact spring, and means for moving said pivoted member in a direction parallel to the longitudinal axes of said tip connectors.

`11. In combination, a' multiple jack having sleeve elements, a multifinger plug having a plurality of flexibly mounted plug fingers each of which includes Aa sleeve and a contact element slidably housed therein, said plug sleeves adapted to fit into corresponding sleeve elements of said Jack, and means for locking said plug in said Jack comprising manually operable means for spreadv 'ing the sleeves ofcertan of said plug fingers to cause them to frictionally lock in their ,corref sponding jack sleeves. l

12,. In a plug-type electrical connector, a plurality of plug lingers each having asleeve and a tip connector longitudinally displaceable relative 

